Prior art methods for producing osteotomies to correct angular deformity in a bone mass, such as a femur or tibia, generally require making a large open incision around the deformed site and cutting a wedge, at such site, completely across the deformed bone mass, to initially form two bone pieces. Once the cut has been made in the bone mass and the wedge removed, the bone pieces may be realigned and the angle between the two bone pieces adjusted for corrective purposes. However, because of the invasiveness of the surgery, osteotomy procedures often result in undesirable pain and extended period of immobility for the patient.
In addition to a period of immobility, prior art methods for producing osteotomies have allowed only minimal control of the bone pieces once the bone mass has been divided. For example, as it may be difficult to control the alignment between the two bone pieces of the deformed bone, the correction of the angular deformity may provide clinical results that are unpredictable. Also contributing to the unpredictability of the clinical results is the difficulty in maintaining the bone pieces in approximation after they have been aligned. Moreover, current osteotomy procedures typically involve application of a uniform corrective angle to the bone pieces, regardless of the individual. As individuals vary in height, weight and age, a slight difference in the angle of a deformed bone mass can cause a measurable difference in contact pressure between the articular surfaces of a deformed bone mass and another bone mass (e.g., between a deformed tibia and a femur). A uniform change in the angle of the deformed bone mass for different individuals, therefore, may not result in a sufficient change in the contact pressure between the articular surfaces of the bones, so as to avoid future degenerative problems.
Accordingly, there is a need for a method that produces osteotomies in a minimally invasive, predictable, and measurable manner, in addition to being individualized and reliable, so that the procedure may be performed at an early stage in the course of the disease. Such a method would permit avoidance of severe degenerative changes that frequently accompany current methods for producing osteotomies.